# 5.1 Concrete Shear Walls

The building satisfies the Quick Check of the shearing stress in the shear walls.

For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. Generate the lateral loads using the Quick Check procedure of Section 2.4.7.3. If *v _{avg}* is greater than 50 psi (or square root of

*f'*if

_{c}*f'*is known), a more detailed evaluation of the structure shall be performed. This evaluation shall employ a more accurate estimation of the level and distribution of the lateral loads, using the analysis procedures in Article 2.

_{c}All shear walls have *h _{w}/l_{w}* ratios less than 4 to 1.

For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the required resistance to overturning moments. Calculate the resistance to the required overturning moments. The overturning resistance shall include the resistance contributed by wall flanges, friction on piling, earth over foundations, and floor and roof weights supported by the wall. The calculated resistance shall be greater than 0.75 times the base moment of the shear wall. The overturning resistance moment may be taken as the righting moment about an edge of the footing or the wall flexural capacity, whichever is less.

The stirrups in all coupling beams are spaced at *d/2* or less and are anchored into the core with hooks of 135 degrees or more.

For buildings designed and constructed in accordance with the 1989 or later editions of Part 2, Title 24, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the strength of the coupling beams. Assume that the beams yield. Calculate their end-moment capacity based either on flexural yield or shear capacity, whichever is lower. The coupling beam moment capacity should include the contribution of a reasonable portion of the adjacent floor slab reinforcement when this reinforcement is in tension. Analyze the walls as independent walls with these restoring moments or shears helping to stabilize the walls. Check the stability of the wall and the stresses in the vertical boundaries. Conforming buildings which fail this check shall be placed in SPC 4, and no calculations are necessary.

Steel column splice details in shear wall boundary elements can develop the tensile strength of the column.

For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the strength of the splice in the boundary column. Determine the maximum tensile column load in each case and verify the adequacy of the splice to resist this load, including gravity loads. Check the adequacy of the splice connection for all gravity and seismic loads. Amplify the seismic load for partial-penetration welded splices by the factor *C _{d}*/2, but not less than 1.5, when the seismic load produces tension at the splice.

There is positive connection between the shear walls and the steel beams and columns.

For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the adequacy of the connections between the shear wall and the beams and columns that are its boundary elements. Calculate the effective overturning demand for the walls and check the adequacy of the shear transfer to the steel elements. A value for shear friction between steel and concrete shall be included only if the steel element is completely encased with reinforced concrete.

For shear walls with *h _{w}/l_{w}* greater than 2.0, the boundary elements are confined with spirals or ties with spacing less then 8

*d*.

_{b}For buildings designed and constructed in accordance with the 1989 or later editions of Part 2, Title 24, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the ductility of the vertical boundary elements that are required to resist large axial forces. Check the need for boundary elements, per ACI 318. Where boundary elements are required but not provided, amplify the seismic forces for the entire structure by the factor 1.25 (and use 0.8*C _{d}* for drift calculation). Conforming buildings which fail this evaluation statement shall be placed in SPC 4, and no calculations are necessary.

The total reinforcing steel for concrete walls is greater than 0.0025 times the gross area of the wall along both the longitudinal and transverse axes and the maximum spacing of reinforcing steel is 18 inches.

For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the quantity of reinforcing in the wall. Calculate the capacity of the walls with the reinforcing that is provided, but amplify the seismic forces by the factor 1.25 (and use 0.8*C _{d}* for drift calculation). Where the reinforcing in the wall is less than 0.0015 times the gross area of the wall along the longitudinal or transverse axis, or if the reinforcing steel spacing exceeds 18 inches, the contribution of the wall to lateral strength and stiffness of the building shall be ignored and, if it is a bearing wall, the building shall be placed in SPC 1.

There is special wall reinforcement around all openings.

For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the reinforcing in the piers and spandrels. Determine the capacity of the spandrels and piers considering all available reinforcing steel that crosses the critical sections.

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*walls*and check the adequacy of the

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*walls*is greater than 0.0025 times the gross area of the

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